Formation of locking keys for fasteners

ABSTRACT

A method of forming a locking key to be received within a groove in a threaded fastener, by initially forming a mounting portion of the key to a width not substantially greater than the groove, and then locally upsetting a predetermined region of that mounting portion to form a widened fin adapted to cut an undercut guideway recess in the sidewall of the groove upon installation therein.

United States Patent Inventor Robefl Neuschotz 1162 Angelo Drive, Beverly Hills, Calif. 90210 Appl. No. 20,293

Divisionof Ser. No. 798,659, Feb. 12, 1969. Filed Mar. 17,1970

FORMATION OF LOCKING KEYS FOR FASTENERS 4 Claims, 17 Drawing Figs.

US. Cl 72/374, 72/377, 29/525 Int. Cl B21k1/76, 821d 53/24 Field 01 Search 72/373,

[56] References Cited UNITED STATES PATENTS 185,633 12/1876 Enochs 85/7 2,195,598 4/1940 Olson 29/525 2,370,171 2/1945 Jepson r 85/7 3,346,031 10/1967 Neuschotz 151/23 Primary Examiner-Lowell A. Larson Attorney-William P. Green ABSTRACT: A method of forming a locking key to be received within a groove in a threaded! fastener, by initially forming a mounting portion of the key to a width not substantially greater than the groove, and then locally upsetting a predetermined region of that mounting portion to form a widened fin adapted to cut an undercut guideway recess in the sidewall of the groove upon installation therein.

PATENTED JULZD ISYI 3, 593. 55 O SHEET 1 OF 2 IN'VENTOR. R0852 r NEUSCHOTZ IQT-TOQJEY SHEET 2 OF 2 Fr 2 15 33b INVENTOR.

Ross/2r NEuscHoTZ 29b 4 lQc FORMATION OF LOCKING KEYS FOR FASTENERS This application is a division of my copending application, Ser. No. 798,659, filed Feb. 12, 1969 on Formation And Use Of Fasteners Having Keys.

CROSS REFERENCE TO RELATED APPLICATION Certain features of the present disclosure are shown and claimed in my copending application, Ser. No. 798,686, filed Feb. 12, 1969 on Structure And Use Of Fasteners Having Locking Keys.

BACKGROUND OF THE INVENTION This inventions relates to fasteners of a type having a thread adapted to be connected to a coacting part, and including a locking key for securing the thread against detachment from the other part.

In my U.S. Pat. No. 2,855,970, issued Oct. 14, 1958 on Insert Having Frictionally Retained Key Which Upsets Threads of Base Member," I have disclosed a type of fastener having a locking key which projects into a groove in the fastener body, and which is driveable axially relative to the fastener body, at the time of connection of the fastener to a coacting part, to lock these parts against detachment. The key in that prior arrangement is retained within the groove by forming the latter to an undercut or dovetail cross section, which effectively confines the key against movement radially out of the groove. That cross section also guides the key during its subsequent generally axial displacement to the ultimate locking position.

In the manufacture of fasteners of the type shown in my above discussed prior U.S. Pat. No. 2,855,970, one difficult and relatively expensive step in the process of manufacture has been the step of shaping the key-retaining grooveto its desired undercut cross section. For most sizes of fasteners, it is impossible or impractical to mill the groove by a single cutter to such an undercut section, and as a result it has normally been necessary to first mill the groove to a nonundercut shape, and then utilize a small and very fragile broaching tool, inserted axially into the groove, to undercut the sidewalls of the groove to the ultimate desired shape. These broaching tools require frequent sharpening, and may break during the broaching operation, or may relatively rapidly wear to a condition in which they are unable to give to the groove a sut'ficiently precise dovetail dimension to assure proper frictional retention of the key in the groove.

SUMMARY OF THE INVENTION The U.S. Pat. application, Ser. No. 798,659, on which the present divisional case is based claims a unique process by which a fastener of the type shown in my above-mentioned prior U.S. Pat. No. 2,855,970, or of any other type utilizing a key retained and driveable within a groove, may be manufactured without the necessity for shaping the groove to an undercut cross section prior to insertion of the key Within the groove. As a result, the groove may be formed very simply and rapidly by a single milling cutter, with much less expense and difficulty than has been encountered in the past.

The requirement for preshaping of the groove to dovetail configuration is avoided by utilizing a keywhich will function, when initially driven generally axially into the nonundercut groove, to itself cut or deform the groove from nonundercut to undercut shape. Preferably, the key has edges at two opposite sides thereof both of which serve to form shallow elongated guideway recesses in two opposite sidewalls of the groove, as the key is driven axially into the groove, so that these recesses give to each of the walls the desired undercut shape, and effectively confine the key against displacement radially from the groove. The edges are for best results shaped to have a camming configuration, so that as the key is driven axially the edges tend to cam or urge the key radially more deeply into the groove, to thus always assure proper positioning of the key in the groove.

The present divisional application covers certain novelty relating to a preferred method of forming the locking key for a fastener of the above discussed type. Specifically, the key is made by a process which includes first forming a mounting portion of the key to a width not substantially greater than that of the groove within which the key is to be received, and then locally upsetting a predetermined region of that mounting portion of the key to form a laterally projecting fin which is wider and thinner than the remainder of the mounting portion. Upon installation of the key in a groove, this fin or a plurality of such fins form undercut guideway recesses in a sidewall or sidewalls of the groove to confine the key within the groove.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawings, in which:

FIG. 1 is an axial section through a threaded insert having keys which may be formed by the process of the present invention, the insert being shown positioned within a carrier part;

FIG. 2 is an enlarged fragmentary view taken on line 2-2 of FIG. 1, but showing only the insert and not the carrier part;

FIGS. 3, 4 and 5 are fragmentary cross sections taken on lines 3-3, 4-4 and 5-5 respectively of FIG. 2;

FIG. 6 is a side view ofthe key only;

FIG. 7 is a fragmentary representation of the mounting portion of a variational type of key which may be formed by the process of the invention;

FIG. 8 is a side view ofthe FIG. 7 key;

FIG. 9 is a section taken on line 9-9 of FIG. 7;

FIG. 10 is a side view of a forging die being utilized for forming the fins on FIG. 7 key;

FIG. 11 is a section taken on line ll-lll of FIG. 10;

FIG. 12 is a front view of another variational type of key;

FIG. 13 is a side view of the key of FIG. 12, taken on line 13-13 of FIG. 12;

FIG. 14 is a bottom view of the key, taken on line 14-14 of FIG. 13;

FIG. 15 is across section taken on line 15-15 of FIG. 14;

FIG. 16 is a fragmentary essentially axial section through another form of insert; and

FIG. 17 is a section taken on line 17-17 of FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing first the arrangement shown in FIGS. I6, and withreference particularly to FIG. 1, I have shown at 10 a fastener typically taking the form of an internally and externally threaded insert, with the fastener being shown positioned within a carrier part 11. The fastener includes a rigid threaded body 12, preferably formed of an appropriate metal such as steel, and one or more (typically two) locking keys 13 for locking the fastener body against removal from the carrier part. The carrier part may be formed of an appropriate rigid material, such as aluminum, a resinous plastic material, or the like, and contains a passage 14 having an internal thread 15 centered about an axis 16. The axially outer surface 17 of the carrier part may be planar and disposed transversely of axis 16, with a tapering frustoconical countersink surface 18 being provided at the axially outer end (upper end) of thread 15 Fastener body 12 has an external thread 19 dimensioned in correspondence with and adapted to be screwed into internal thread 15 of the carrier part. Both of these threads may be of completely standard configuration except for the provision of modified minor diameter surfaces 20 having a diameter and an axial extent which are greater than theywould be if the threads were entirely standard.

Internally, the fastener body 12 has a second thread 21, which may be standard in form, and into which a coacting threaded screw or study may be connected, to secure the screw or stud to the carrier part through the medium of fastener body 12. The axially outer end of body 12 may have a substantially annular end surface 22 which is desirably planar and disposed transversely of axis 16, and which in the installed FIG. 1 position of the insert body is located substantially flush with, or preferably slightly under a flush position with respect to, the planar outer surface 17 of the carrier part.

Each of the locking keys 13 of the fastener is frictionally held in the FIG. 1 outwardly projecting position with respect to fastener body 12 prior to and during installation of the fastener within the carrier part. Each key has an axially inner mounting portion 23 which is relatively thin in a direction radially of axis 16, and which is received and held within a mounting groove 24 extending axially along the outer surface of body 12. Axially outwardly beyond mounting portion 23, each key has a radially thicker locking portion 25, which projects axially beyond outer end surface 22 of the insert body 12, and has an end surface 26' adapted to be engaged by a hammer or other driving tool to drive the key axially inwardly to the broken line locking position 13 ofthe right-hand key in FIG. 1. In this locking position, the outer end surface 26 of the key is desirably substantially flush with outer end surface 22 of the insert.

Prior to installation of the keys within grooves 24, each groove may be formed to the nonundercut cross section illustrated in FIG. 5. More particularly, the groove may have a rectangular cross section transversely of axis 16, being defined at its radially inner side by an inner planar wall surface 26 extending parallel to axis 16 and perpendicular to a radial line 27 from that axis. The opposite sides of groove 24 may be defined by two parallel planar opposite sidewall surfaces 28, both lying parallel to axis 16, and parallel to and spaced equal distances from radial line 27, and perpendicular to inner wall 26 of the groove. In the fonn of the invention shown in FIGS. l6, the above discussed cross section of each groove is initially uniform and unchanging through the entire length of the groove. The inner wall surface 26 of the groove is located radially inwardly beyond the minor diameter of internal thread in the carrier part, and in most instances also inwardly of the minor diameter of insert thread 19, to provide a space within which the thin mounting portion 23 of key 13 can be received without contacting or interfering with thread 15 as the insert is screwed into the carrier part. The groove is illustrated as continuing through the entire length of the insert, but may of course extend through only a portion of that length if desired.

Portion 23 of the key has a planar surface 29 at its radially inner side slidably engageable with inner wall surface 26 of groove 24, and has a radially outer surface 30 which may also be planar and disposed parallel to surface 29 at approximately the location of minor diameter surfaces of thread 19. At its opposite sides, portion 23 of each of the keys is defined by two parallel axially extending opposite side surfaces 31, disposed perpendicular to surfaces 29 and 30, and preferably spaced apart a width dimension w slightly less than the width of the groove between its opposite sidewalls 28. Projecting laterally from the opposite sides of mounting portion 23, each key has one or more pairs of fins 32, typically three pairs as seen in FIG. 2, which fins act upon installation of the key within groove 24 to deform the groove to the undercut cross section of FIG. 3. These fins may be formed by locally upsetting or forging the metal forming the key 13 at the location of each of the fins, to give the fin the shape illustrated in FIGS. 2-6. More particularly, as seen in FIGS. 2, 3 and 6, each fin has an outer lateral edge 33 (see especially FIG. 2) which projects a short distance laterally beyond the plane of sidewall surfaces 31 of portion 23, and which advances progressively laterally inwardly toward the inner end 34 of the key. As seen in cross section in FIG. 3, the fins may have planar undersurfaces 34' forming continuations of the previously mentioned surface 29, and may have radially outer surfaces 35 which converge downwardly toward undersurface 29-24 in advancing laterally. As indicated in the side view of FIG. 6, surfaces 35 also desirably converge toward the plane of surface 29 as surfaces 35 advance axially inwardly toward the inner end 34 of the key.

In most instances the overall width d of the key at the location of each pair of fins (FIG. 3) is only a few thousandths of an inch (preferably between about 0.006 and 0.012 of an inch) greater than the width dimension e between the opposite sidewall surfaces 28 of the groove, and preferably between about 0.008 and 0.014 of an inch greater than the width dimension w between the side surfaces 31 of portion 23 of the key. The difference between the dimensions 2 and w should also preferably be not greater than a few thousandths of an inch, desirably between about 0.001 and 0.004 ofan inch.

The relatively thick axially outer locking portion 25 of each key projects radially outwardly far enough to cut through and deform the internal thread 15 of the carrier part when the key is driven axially from the full line position of FIG. l,to the broken line position of the right hand key in that figure. At its axially inner end, portion 25 has a shoulder 36 which cuts through the material of the carrier part, and which during initial installation engages countersink surface 18 in a manner limiting the extent to which the fastener assembly can be screwed into the carrier part, and therefore accurately predetermining the slightly underflush setting of outer surface 22 of the insert relative to surface 17 of the carrier part.

As previously indicated, the insert body 12 is first formed with its grooves 24 having the FIG. 4 nonundercut cross section along the entire length of the insert. After the body 12 has been formed to this condition, and prior to installation of body 12 within a carrier part, each of the keys 13 is driven axially into the corresponding groove 24 to the position illustrated in FIG. 2, and illustrated in full lines in FIG. 1. During such advancement of the keys into the grooves, fins 32 deform or cut through the material of body 12 at the base of each of the sidewalls 28 of the groove, to form axially extending elongated guideway recesses 37 (FIGS. 3 and 4) at the base of those sidewalls, and thereby give sidewalls 28 an undercut cross section as seen clearly in FIG. 3. The fins 32 are tightly frictionally confined within the undercut guideway recesses 37 in a manner tightly frictionally holding each key 13 in the full line position of FIG. 1 relative to body 12, and by virtue of the undercut arrangement retaining the keys against radially outward displacement from the grooves. Axially inwardly beyond the leading pair of fins 32 of each key, the groove 24 of course retains its original FIG. 5 nonundercut cross section. It is also noted that, by virtue of the camming angularity of outer surfaces 35 of the fins, as seen in the side view FIG. 6, these surfaces tend to cam or urge the key radially inwardly tightly against inner surface 26 of the groove, to assure proper positioning of the key within the radially inner portion of the groove.

After the keys 13 have been installed within body 12 to the FIG. 1 position, the fastener body 12 and keys can be handled as a single essentially integral unit, with the outwardly projecting keys being utilized for assisting in screwing the body 12 into carrier part 11. The assembly is advanced into the carrier part until engagement of the keys with countersink surface 18 halts such advancement, following which the keys are driven axially inwardly until their outer ends 26 are flush with surface 22 of the body 12. During this final driven movement of the keys within grooves 24, fins 32 act to form axially inner extensions or continuations of the guideway recesses 37 of FIGS. 3 and 4, and act to continue camming the keys radially inwardly against surface 26 to maintain proper positioning of the keys within the grooves.

FIGS. 79 illustrate a variational form of key 13a which may be substituted for the keys 13 of FIG. 1, and which can be identical with key 13 except as to a slight change in the configuration of the laterally projecting fins 32a, corresponding to fins 32 of FIGS. l6. In FIGS. 79, the outer or lateral edges 33a of the fins may at their leading ends be rounded or curved, as indicated at 1330 in FIG. 7, to facilitate advancement of the fins into the material of the carrier part, and to assure proper formation of guideway recesses corresponding to recesses 37 of FIGS. 3 and 4. Axially outwardly beyond their rounded leading ends, edges 33a may converge gradually and progressively toward the planes of sidewall surfaces 31a of the key, as seen clearly in FIG. 7.

In forming the key of FIGS. 7-9. its thin portion 230 may first be shaped to have a uniform rectangular cross section along its entire length, with planar surfaces 310 continuing without interruption even through the locations at which the fins are ultimately formed. This uniform cross section portion 230 of the key may then be upset, to form one or more pairs of fins 320, by a forging tool such as that illustrated at 38 in FIGS. 10 and 11. If two pairs of fins are to be provided, as shown, this forging tool may include two identical rigid forging dies 39 secured together by a suitable rigid connector structure 40, and each having an arcuate forging undersurface 41 (FIG. 11) which strikes downwardly against portion 23a of the key to deform it at two opposite side locations 42 in a manner forming two opposed fins. During this forging operation, the portion 230 of the key may rest on and be supported by a rigid anvil or backing surface 43, acting to maintain or produce whatever configuration is desired at the underside of the key (a completely planar undersurface configuration in the key of FIGS. 7-9). The forging surfaces 41 of the two elements 39 are given appropriate angularities to cause radially outer surfaces 35a of the fins (FIG. 9) to have a camming angularity similar to that described in connection with surfaces 35 of FIG. 6, and for the same purpose. That is, surfaces 35a advance progressively away from the plane of undersurface 29a of the key as they advance axially outwardly (upwardly in FIG. 8). The use of the key of FIGS. 711 is of course the same as has been discussed in connection with the first form of key illustrated in FIGS. l6, and need not be reiterated.

FIGS. l2--is show another form of locking key 13b which may be substituted for the key 13 or 13a of the other forms of the invention. This key 13b may be considered as substantially identical with key 13, except for a difference in the configuration of the laterally projecting fins 32b. More specifically, there may typically be only two fins in FIGS. l2-15, and these fins may be formed by first giving the thin portion 23b of the key a uniform rectangular cross section along its entire length, from the inner end portion 34a to the location 44 of FIG. 12, and then upsetting or forging portion 23b near its opposite side edges from the under or inner side of the key (left side in FIG. 13), to cause the fins to project laterally outwardly a few thousandths of an inch. The forged surfaces 45 and the opposite surfaces 46 on each of the fins 32b may both advance at a camming angularity corresponding to that of surface 35in FIG. 6, and for the same purpose, (camming angle x in FIG. 13) to tend to cam the key radially inwardly against the inner wall surface 26 of groove 24 in FIGS. 3 and 4, both during initial partial installation of the key within the groove, and subsequent advancement of the key to its ultimate locking position. As in the first form of the invention, the lateral edges 33b of the fins 32b in FIGS. 12-15 converge progressively toward one another and toward the parallel planes of the main portions of sidewall surfaces 311: as edges 33b advance toward the axially inner end 340 of the key, to thus facilitate deformation of the sidewalls of the groove in the fastener body to their desired undercut configuration, for tightly confining and retaining the keys in their partially installed positions within the grooves.

With reference to the cross-sectional view FIG. 15, it is preferred that the upset surfaces 45 of the key be planar, and desirably that the angle b in FIG. representing the angularity in a transverse plane between surfaces 45 and undersurface 29b of the key be between about 10 and 30.

In the final arrangement shown in FIG. 16, which it may be noted includessome features covered in my copending application, Ser. No. 798,686, the axially outwardly projecting portion 25c of the key 13c is no thicker than the axially inner mounting portion 23c which is received and frictionally retained within groove 24: in body 12c. To attain a locking action without the necessity for the thickened axially outer portion of the key, the groove and particularly its radially inner wall surface 26c3r e s h age gl to cu ve gradually radially outwardly as they advance axially inwardly, so that in the FIG. 16 position the key will not interfere with screwing of the insert into carrier part 116, and yet when driven axially inwardly the key will be deflected or directed slightly radially outwardly toward the material of the carrier part, to cut through and deform the threads of the carrier part and lock the insert against removal. Other similar arrangements for directing a key radially as it advances axially, to attain a locking action without the necessity for a thickened! outer portionof the key, are shown in my above mentioned application, Ser. No. 798,686, and may be used in conjunction with the features of the present invention.

In FIG. 16, the fins 32c are typically illustrated as not having the camming angularity of the previously illustrated forms of the invention. Instead, fins 320 are relatively long, desirably extending along essentially the entire axial length of the mounting portion 230 of the key, and may be of completely uniform and unchanging transverse cross section (typically the cross section of FIG. 17) through the entire length of the fins. These fins may be formed by a forging process similar to that discussed previously in connection with FIGS. 10 and 11, and can if desired have the shortened configurations of FIGS. 2, 8, I0, 13, etc. rather than the lengthened form shown in FIG. 16. When this finned portion of the key is driven into the initially nonundercut groove 24c, fins 32c cut or form undercut guideways in the sidewalls of the groove, to retain the key frictionally in the FIG. 16 position in the groove. During such installation of the key in the groove, the key may be engaged by a suitable locating tool, and be held by that tool inwardly against the inner wall 260 of the groove.

For determining the extent to which the insert of FIG. 16 may be screwed into the carrier, the external thread of body 12c may have its axially outer turn 119 deformed axially inwardly as illustrated, to form a stop shoulder acting to limit advancement of the insert into the carrier part at the FIG. 16 slightly underflush position.

While I have typically described certain specific embodiments of my invention, it is of course to be understood that the invention is not limited to these particular forms, but rather is applicable broadly to numerous variations falling within the scope of the appended claims.

Iclaim:

1. The method of forming an elongated locking key to be received within a groove of predetermined width extending at least partially through a thread of a fastener body, said method comprising forming a mounting portion of said key having a width not substantially greater than that of said groove for reception therein and having a thickness dimension less than said width, then forging said mounting portion of the key between two opposed forging dies, applying forging force to said mounting portion by said dies in essentially the direction of said thickness dimension and primarily at two opposite side edges of the mounting portion in a relation forming two fins at said opposite side edges which project laterally farther than said edges did prior to forging and which are thinner than said edges were before forging and which are adapted to cut two undercut guideway recesses in opposite sidewalls of said groove as the mounting portion is driven thereinto, and leaving an intermediate region of said mounting portion of the key between said two fins substantially thicker than the fins.

2. The method as recited in claim 1, including shaping said edges during said forging operation so that said fins taper progressively to a reduced thickness as they advance laterally outwardly. I

3. The method asrecited in claim 1, including shaping said edges during said forging operation so that said fins have outer camming surfaces which advance progressively inwardly in the direction of the thickness of said mounting portion as they advance axially inwardly.

4. The method as recited in claim 1., including shaping said edges during said forging operation so that said fins taper progressively to a reduced thickness as they advance laterally outwardly, and so that said fins have outer camming surfaces which advance progressively inwardlyiii 55 directionk f th e thickness of said mounting portions as they advance axially inwardly. 

1. The method of forming an elongated locking key to be received within a groove of predetermined width extending at least partially through a thread of a fastener body, said method comprising forming a mounting portion of said key having a width not substantially greater than that of said groove for reception therein and having a thickness dimension less than said width, then forging said mounting portion of the key between two opposed forging dies, applying forging force to said mounting portion by said dies in essentially the direction of said thickness dimension and primarily at two opposite side edges of the mounting portion in a relation forming two fins at said opposite side edges which project laterally farther than said edges did prior to forging and which are thinner than said edges were before forging and which are adapted to cut two undercut guideway recesses in opposite sidewalls of said groove as the mounting portion is driven thereinto, and leaving an intermediate region of said mounting portion of the key between said two fins substantially thicker than the fins.
 2. The method as recited in claim 1, including shaping said edges during said forging operation so that said fins taper progressively to a reduced thickness as they advance laterally outwardly.
 3. The method as recited in claim 1, including shaping said edges during said forging operation so that said fins have outer camming surfaces which advance progressively inwardly in the direction of the thickness of said mounting portion as they advance axially inwardly.
 4. The method as recited in claim 1, including shaping said edges during said forging operation so that said fins taper progressively to a reduced thickness as they advance laterally outwardly, and so that said fins have outer camming surfaces which advance progressively inwardly in the direction of the thickness of said mounting portions as they advance axially inwardly. 